internal void Accept(NodeAs a)
{
a.value.Visit(this);
a.type.Visit(this);
builder.OpAs();
}
void ASTVisitor.Accept(NodeAs value)
{
Accept(value);
}
private Node Postfix(Node node, bool allowPostfixInvocation)
{
if (node == null || !TokensRemain)
return node;
// handle { i+ = 1 } assign operators
if (HasNextToken && Current.type == OPERATOR && Next.type == ASSIGN)
{
string op = Current.image;
Advance(); Advance();
var right = Expression();
if (right == null)
{
// TODO error
}
return new NodeAssign(node, new NodeInfix(node, right, op));
}
switch (Current.type)
{
case ASSIGN: Advance(); return new NodeAssign(node, Expression());
case OPEN_BRACE:
if (Location.line != node.EndLine || !allowPostfixInvocation)
break;
Advance();
List<Node> args;
if (!Check(CLOSE_BRACE))
args = CommaExpressions();
else args = new List<Node>();
Expect(CLOSE_BRACE, "Expected a close brace (')') to end the function argument list.");
return Postfix(new NodeInvoke(node, args), allowPostfixInvocation);
case OPEN_SQUARE_BRACE:
if (Location.line != node.EndLine)
break;
Advance();
if (Check(OPERATOR) && HasNextToken && Next.type == CLOSE_SQUARE_BRACE)
{
node = new NodeOperatorIndex(node, Current.image);
Advance();
}
else if (Check(CLOSE_SQUARE_BRACE))
{
Advance();
log.Error(Location, "At least one argument is needed to index an object.");
return node;
}
else node = new NodeIndex(node, CommaExpressions());
Expect(CLOSE_SQUARE_BRACE, "Expected a close brace (']') to end the operator index.");
return Postfix(node, allowPostfixInvocation);
case DOT:
Advance();
// TODO do other checks, such as infix/prefix/as
// for now, just check identifier indexing.
string ident;
ExpectIdentifier(out ident, "Identifier expected for field indexing.");
return Postfix(new NodeFieldIndex(node, ident), allowPostfixInvocation);
case AS:
Advance();
if (!TokensRemain)
{
log.Error(tokens[-1].location, "Expected expression for 'as' cast, but the end of the file was reached.");
break;
}
var type = PrimaryExpression();
if (type == null)
{
log.Error(tokens[-1].location, "Expected expression for 'as' cast.");
break;
}
var a = new NodeAs(node, type);
return a;
}
return node;
}
